Propofol is widely used by anaesthesiologists for deep sedation and general anaesthesia. During recent years nurses trained in the use of low dose Propofol sedation (NAPS) during endoscopy have been introduced. The method has been implemented at the endoscopic unit at Gentofte hospital since 2008(1). Propofol has a respiratory depressive effect which may result in depressed oxygen saturation in the blood (hypoxia). Due to a short acting half life this is prevented in the majority of cases. However, in spite of this, hypoxia is experienced in 4,4% of patients receiving propofol during endoscopy at Gentofte Hospital (unpublished data). It is well known that hypoxia constitutes a late expression of reduced oxygen tension in peripheral tissues. Whether the addition of capnography to standard monitoring during NAPS may be of benefit is widely unknown. The aim of this study is to examine whether the additional use of capnography to standard monitoring during endoscopy may improve patient safety in patients undergoing low dose Propofol sedation by reducing the number, duration and level of hypoxic events. The trial is a randomized clinical prospective case-control study.

Further study details as provided by University Hospital, Gentofte, Copenhagen:

Primary Outcome Measures:

The number of hypoxic events [ Time Frame: The sum of events registered during procedures (procedure duration is, depending on the type, 3 to 90 minutes) ] [ Designated as safety issue: Yes ]

If the addition of capnography to standard monitoring can reduce the number of hypoxic events in patients undergoing endscopy with NAPS. A hypoxic event is defined as an observed oxygen saturation of less than 92% . Data is collected by a computer with intervals of 12 sec as the smallest possible.

Whether more or less actions are taken against respiratory insufficiency with or without capnography in patients undergoing endoscopy with NAPS.

The duration of hypoxia [ Time Frame: The sum of time with hypoxia registered during procedures (procedure duration is, depending on the type, 3 to 90 minutes) ] [ Designated as safety issue: Yes ]

The duration of hypoxia is measured as the sum of registrations(each registration represents 12 seconds) with an oxygen saturation of less than 92 percent. Data is collected by a computer with intervals of 12 sec as the smallest possible.

The level of hypoxia [ Time Frame: The sum of events registered at each level during procedures (procedure duration is, depending on the type, 3 to 90 minutes) ] [ Designated as safety issue: Yes ]

Intervention group with the addition of capnography to standard monitoring (non-invasive blood pressure, pulse, pulse oximetry, clinical observation of respiration, electrocardiography (ECG) and respiratory frequency measured by the ECG)

Device: Capnography (Phillips MP20 monitor)

In the intervention group the NAPS nurse observed possible hypoxia and changes in capnography curves/values during the procedure and was instructed to decrease propofol and take actions against insufficient ventilation* if etCO2 ≥ 7kPa or ≤ 2 kPa for ≥ 1 minute, if respiratory frequency ≤ 8 or a loss of curve shape was registered.

Control group without the addition of capnography to standard monitoring (non-invasive blood pressure, pulse, pulse oximetry, clinical observation of respiration, electrocardiography (ECG) and respiratory frequency measured by the ECG)

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Please refer to this study by its ClinicalTrials.gov identifier: NCT01507623